CVE-2021-0955

Local privilege escalation via FuseDaemon use-after-free

Published Dec 15, 2021 · Updated Aug 3, 2024

Use-after-free in Android 11 Framework allows local users to escalate privileges through a race in FuseDaemon write handling. In pf_write_buf, fuse_reply_write can let pf_release destroy a file handle before the fadvise queue records the write, causing Record to use the freed handle. A low-privileged local process can trigger the race without user interaction and gain higher privileges; no remote path is reported.

CVSS severity7.0
High
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Android 11 Framework allows local users to escalate privileges through a race in FuseDaemon write handling. In pf_write_buf, fuse_reply_write can let pf_release destroy a file handle before the fadvise queue records the write, causing Record to use the freed handle. A low-privileged local process can trigger the race without user interaction and gain higher privileges; no remote path is reported.

The record

CVE
CVE-2021-0955
Published
Dec 15, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-362, T1404
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Android-11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Google Cloud · Androidversion=Android-11

Published CVSS scores

6.9NVDAV:L/AC:M/Au:N/C:C/I:C/A:C
7.0NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1404Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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